LXR linux/include/linux/mman.h

   1#ifndef _LINUX_MMAN_H
   2#define _LINUX_MMAN_H
   3
   4#include <linux/mm.h>
   5#include <linux/percpu_counter.h>
   6
   7#include <linux/atomic.h>
   8#include <uapi/linux/mman.h>
   9
  10extern int sysctl_overcommit_memory;
  11extern int sysctl_overcommit_ratio;
  12extern struct percpu_counter vm_committed_as;
  13
  14#ifdef CONFIG_SMP
  15extern s32 vm_committed_as_batch;
  16#else
  17#define vm_committed_as_batch 0
  18#endif
  19
  20unsigned long vm_memory_committed(void);
  21
  22static inline void vm_acct_memory(long pages)
  23{
  24        __percpu_counter_add(&vm_committed_as, pages, vm_committed_as_batch);
  25}
  26
  27static inline void vm_unacct_memory(long pages)
  28{
  29        vm_acct_memory(-pages);
  30}
  31
  32/*
  33 * Allow architectures to handle additional protection bits
  34 */
  35
  36#ifndef arch_calc_vm_prot_bits
  37#define arch_calc_vm_prot_bits(prot) 0
  38#endif
  39
  40#ifndef arch_vm_get_page_prot
  41#define arch_vm_get_page_prot(vm_flags) __pgprot(0)
  42#endif
  43
  44#ifndef arch_validate_prot
  45/*
  46 * This is called from mprotect().  PROT_GROWSDOWN and PROT_GROWSUP have
  47 * already been masked out.
  48 *
  49 * Returns true if the prot flags are valid
  50 */
  51static inline int arch_validate_prot(unsigned long prot)
  52{
  53        return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
  54}
  55#define arch_validate_prot arch_validate_prot
  56#endif
  57
  58/*
  59 * Optimisation macro.  It is equivalent to:
  60 *      (x & bit1) ? bit2 : 0
  61 * but this version is faster.
  62 * ("bit1" and "bit2" must be single bits)
  63 */
  64#define _calc_vm_trans(x, bit1, bit2) \
  65  ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
  66   : ((x) & (bit1)) / ((bit1) / (bit2)))
  67
  68/*
  69 * Combine the mmap "prot" argument into "vm_flags" used internally.
  70 */
  71static inline unsigned long
  72calc_vm_prot_bits(unsigned long prot)
  73{
  74        return _calc_vm_trans(prot, PROT_READ,  VM_READ ) |
  75               _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
  76               _calc_vm_trans(prot, PROT_EXEC,  VM_EXEC) |
  77               arch_calc_vm_prot_bits(prot);
  78}
  79
  80/*
  81 * Combine the mmap "flags" argument into "vm_flags" used internally.
  82 */
  83static inline unsigned long
  84calc_vm_flag_bits(unsigned long flags)
  85{
  86        return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
  87               _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
  88               _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    );
  89}
  90#endif /* _LINUX_MMAN_H */
  91